How dynamite could help destroy prostate cancer

A chemical once used as a deadly explosive could be a powerful new treatment for prostate cancer.

British scientists have discovered a skin patch containing minute doses of nitroglycerine appears to stop some tumours in their tracks.

Patients who took part in a small clinical trial saw their levels of prostate-specific antigen, a chemical marker in the blood that increases when cancer is present, stabilise.

Researchers believe that, as tiny amounts of the chemical seep into the bloodstream, cancer growth is stemmed by a rise in levels of nitric oxide circulating in the body.

Previous studies have shown prostate tumours appear to thrive in an absence of nitric oxide.

Nitroglycerine is a rich source of both nitrogen and oxygen, two key components of nitric oxide, and was first developed in the 1840s.

It is an oily, colourless liquid that, in large quantities, is so unstable that the slightest jolt can cause it to spontaneously detonate.

In 1864, the Swedish chemist, engineer, innovator and armaments manufacturer Alfred Nobel perfected a way to stabilise the chemical so it could be safely transported. He patented it under the name dynamite.

But his success came only after several explosions in his laboratory in Stockholm, one of which killed his brother Emil and several other colleagues.

Shortly afterwards, it was also discovered that nitroglycerine, in much smaller quantities, had useful medical properties because it was able to dilate blood vessels and improve blood flow.

Nitroglycerine quickly became a popular treatment for chest pain and, for more than 100 years, has been used as a very safe and effective remedy for the heart condition angina.

Thousands of patients in Britain already take nitroglycerine daily to combat chest pain, usually in the form of a pill, skin patch or a mouth spray.

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The latest trial, carried out at Queen’s University in Belfast, came about after researchers there performed laboratory tests that showed the explosive appeared to slow cancer growth.

They recruited 24 men diagnosed with prostate cancer who had undergone either radiotherapy or a radical prostatectomy - surgery to remove the prostate gland. They wore the patch 24 hours a day for two years.

Because laboratory tests suggested the amount of nitroglycerine needed to tackle cancer is much smaller than that used for angina, researchers took a skin patch currently prescribed to heart patients and cut it into six, using just one piece for the cancer patients.

Each man wore a patch on the arm or abdomen, changing it every 12 hours. Doctors checked them every few months for their PSA doubling time, a measure of whether the cancer is returning.

The results, published in the journal Urology, showed that within six months, PSA levels had stabilised in all but five of the 24 volunteers. After a year, most were either still stable or even declining.

Dr Robert Siemens, who led the study, said: ‘We were very excited to see a significant slowing in the progression of the disease, as

evidenced by the men’s PSA levels, and to see this result in many of the men whom completed the study.’

The Queen’s University team plans bigger trials this year to see how many men could benefit from the explosives therapy. But Cancer Research UK warned that although the study shows nitroglycerine can reduce PSA levels, there is still no proof that it actually affects the rate of tumour growth.

Henry Scowcroft, the science information manager at Cancer Research UK, said: ‘This study has several limitations. It only measured men’s PSA levels, rather than how their prostate cancer developed, so its results need to be interpreted with care.’

• A cocktail of tomato and soy juice is being given to men with prostate cancer.

It is hoped the drink may slow the growth of cancer cells, say researchers at the James Cancer Hospital at Ohio State University.

In the new trial the men will take the drink for 28 days before undergoing surgery to remove their prostate. Blood and tissue samples will then be examined to assess the protective effects of the mix.

This follows a number of studies that have suggested that both soy and tomato can reduce the risk of the disease, or even slow its progression.